EBSD analysis
EBSD (Electron Backscatter Diffraction) analysis and XRD (X-ray Diffraction) analysis are two microstructural characterisation techniques for crystalline materials based on the diffraction of radiation by crystalline planes.
They are used to measure the crystallographic orientation of grains, grain size and shape, texture, defects and phases present in a sample.
The main difference between the two techniques is the type of radiation used: electrons for EBSD and X-rays for XRD.
This difference implies advantages and disadvantages for each technique.
- EBSD analysis requires a scanning electron microscope (SEM) and a specific detector, which limits its accessibility and cost. It does, however, provide high spatial resolution (in the nanometre range) and direct visualization of the Kikuchi patterns formed by backscattered electrons.
- XRD analysis requires an X-ray source and a diffractometer, making the technique simpler and more widespread. It allows a larger surface area of the sample to be probed and statistical information on the microstructure to be obtained. The two techniques are complementary for studying the microstructural properties of materials and understanding their mechanical, thermal, electrical or magnetic behaviour.
Electron Backscatter Diffraction (EBSD) and Energy Dispersive X-ray Spectroscopy (EDX) are two complementary techniques used in Scanning Electron Microscopy (SEM) to characterise the microstructure and chemical composition of materials. In this article, we present the principles, advantages and limitations of these two analysis methods.
EBSD analysis measures the crystallographic orientation of grains, grain boundaries, phases and textures in a sample. It is based on the diffraction of electrons backscattered by the atomic planes of the material.
By varying the angle of incidence of the electron beam, it is possible to generate a diffraction pattern characteristic of each crystalline orientation. This pattern is then compared with a database to identify the orientation and phase of the point being analysed. By scanning the beam over an area of interest, it is possible to map the microstructure of the sample with spatial resolution in the nanometre range.
EDX analysis
EDX analysis is used to measure the elemental composition of materials. It is based on the emission of characteristic X-rays by atoms excited by the electron beam. By analysing the spectrum of the X-rays detected, it is possible to identify the elements present in the point analysed and determine their relative concentrations. By scanning the beam over an area of interest, it is possible to map the distribution of chemical elements in the sample with a spatial resolution of the order of a micrometre.
EBSD and EDX analysis are therefore two techniques that provide different but complementary information on the microstructure and chemical composition of materials. They provide a better understanding of the physical, mechanical and functional properties of materials, as well as the mechanisms involved in their development, transformation and ageing.